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Appendix VI.                        noi

axis dd.    Dividing the whole solid into thin rings, w being the
weight of a cubic inch in Ibs. :

I  =   S (ring wt. x ring radius2)

=   S (W-L x vol. x r^)

=  S (2irr^^f'W1rf)

-   27rb wl S (62*. r*)

But S /. r^ is the contents of any square lamina of the pyramid
shewn, multiplied by its respective radius.    Therefore 2 (S/  r^)

F^ig. 97O.

will be the volume of the pyramid multiplied by the arm from
centre d to the centre of gravity of pyramid.

And I  =   27T b wl (vol. of pyramid) f r0

The total weight of the cylinder being W^K r2 b> we have

2

i& =    I -r weight   ^- inches.
Referring again to Fig. 970, let the radii r0 and n represent